Photochromic spironaphthopyran compounds

ABSTRACT

A naphthopyran compound represented by the formula: ##STR1## wherein R 1 , R 2 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10  are each selected from the group consisting essentially of hydrogen, a stable organic radical, a heterocyclic group, a halogen, a nitrogen-substituted group, and a nitrogen-substituted ring compound and wherein A is a substituted divalent aromatic radical that includes substituents selected from the group consisting essentially of hydrogen and the stable organic radical.

This is a continuation of application Ser. No. 08/331,281, filed Oct.28, 1994 now U.S. Pat. No. 5,628,935.

BACKGROUND OF THE INVENTION

The present invention generally relates to naphthopyran compounds. Morespecifically, the present invention relates to photochromicspironaphthopyran compounds and to articles made of photochromicspironaphthopyran compounds.

Photochromism generally concerns the ability of a compound to reversiblychange color under different light conditions. One particular type ofphotochromic phenomenon concerns the reversible change in color of acompound from an original color to a different color when the compoundis exposed to a source of ultraviolet radiation, such as solar radiationor light radiated from a mercury or xenon lamp. The photochromiccompound fades to the original color within a period of time after thephotochromic compound is isolated from the ultraviolet radiation, suchas by placing the compound in a dark room.

Various products, including optical lenses, incorporate the principal ofphotochromism. For example, photochromic compounds, such asnaphthopyrans, are incorporated into plastic ophthalmic lenses to effectcolor changes in the lenses when the lenses are exposed to particularlighting conditions. Additionally, different photochromic compounds maybe blended together to create a color effect that is different fromrespective color effects of the individual photochromic compounds. As anexample, a first photochromic compound that turns orange or red whenactivated by light and a second photochromic compound that turns bluewhen activated by light may be blended together to form a photochromicmixture that produces a shade of gray when activated by light.

Several types of photochromic compounds have been reported which exhibitchanges in color when exposed to ultraviolet light. One particular classof photochromic compounds includes the 3,3-disubstituted naphthopyrans.One specific group of 3,3-disubstituted naphthopyrans includes the3H-naphtho 2,1b!pyrans. The color response of the 3H-naphtho 2,1b!pyransto ultraviolet light extends to purple, red, orange, or yellow,depending upon the composition and structure of the particular3H-naphtho 2,1b!pyrans. A general expression of the 3H-naphtho2,1b!pyrans is provided in graphical formula I: ##STR2## where R_(3a)and R_(3b) are substituents attached to the pyran ring at the positionindicated.

U.S. Pat. No. 3,567,605 to Becker describes chromenes and chromenederivatives which are photochromic at relatively low temperature. TheBecker patent also describes chromenes and chromene derivatives whichare photochromic at room temperature, such as diphenyl-3H-naphtho2,1b!pyran, where R_(3a) and R_(3b) of formula I are each phenyl groups.

U.S. Pat. No. 4,931,221 to Heller et al. describes additionalphotochromic compounds, including 3H-naphtho 2,1b!pyrans represented byformula I, where R_(3a) and R_(3b) are cyclopropyl radicals and whereany of various substituents are included on the naphtho portion of thenaphthopyran rings. Heller reports that the 3H-naphtho 2,1b!pyrans whichinclude cyclopropyl radicals exhibit a larger bathychromic shift in thevisible spectrum, as compared to 3H-naphtho 2,1b!pyrans which includealkyl groups or a spirocycloalkyl group in place of the cyclopropylradicals.

U.S. Pat. No. 5,066,818 to Gemert et al. discloses additionalphotochromic compounds generally meeting graphical formula I. The Gemertpatent reports a range of decolorization rates associated with the3H-naphtho 2,1b!pyrans.

U.S. Pat. No. 5,106,998 to Tanaka et al. describes compounds in whichR_(3a) and R_(3b) of graphical formula I are alkyl groups. Tanakareports several fade times and maximum absorption wavelengths associatedwith the compounds.

U.S. Pat. No. 5,238,981 to Knowles describes naphthopyran compounds ofgraphical formula I in which R_(3a) and R_(3b) are each selected from agroup of organic radicals that include phenyl and naphthyl. Variouspotential substitutions on the naphtho portion of the naphthopyrans ringare taught, including an 8-methoxy substitution. Knowles states thatnumber eight carbon atom substitutions, such as the 8-methoxysubstitution, cause a bathychromic shift in the visible spectrumassociated with activated forms of the 3H-naphtho 2,1b!pyrans and in theultraviolet spectrum of unactivated forms of the 3H-naphtho 2,1b!pyrans.

U.S. Pat. No. 5,244,602 to Van Gemert and U.S. Pat. No. 5,274,132 to VanGemen each describe 3H-naphtho 2,1b!pyrans of graphical formula I thatinclude various radical substitutions at the R_(3a) and R_(3b)positions. Each of these Van Gemert patents also claim to achievebathychromic shifts in the visible spectrum associated with the3H-naphtho 2,1b!pyrans.

Another class of photochromic compounds include spironaphthopyrans, asexpressed in graphical formula II: ##STR3## In formula H, R₃ is attachedto the pyran ring by a spiro carbon, which is a single carbon atom thatis shared by two separate rings. Compounds with a single carbon atomthat is common to two separate rings are called spiro compounds. Veryfew naphthopyrans have been disclosed in which the carbon in the number3 position of the naphthopyran ring is a spiro carbon.

U.S. Pat. No. 4,826,977 to Heller describes a naphthopyran of formula IIwhere R₃ is the adamantyl group. Another patent, U.S. Pat. No. 4,980,089to Heller, teaches a naphthopyran of formula II where R₃ may be abicyclic norcamphane group, a tricyclodecane group, or derivatives ofeither the norcamphane group or the tricyclodecane group.

Additionally, U.S. Pat. No. 5,106,998 to Tanaka et al. describes pyrancompounds, such as that of graphical formula II, in which R₃ is either anorbornylidene radical or a bicyclo 3,3,1!-nonylidene radical. Tanakareports several fade times and maximum absorption wavelengths associatedwith various naphthopyrans that include either the norbornylidene or thebicyclo 3,3,1!9-nonylidene radical.

SUMMARY OF THE INVENTION

The present invention includes a naphthopyran compound represented bythe formula: ##STR4## wherein R₁, R₂, R₅, R₆, R₇, R₈, R₉, and R₁₀ areeach selected from the group consisting essentially of hydrogen, astable organic radical, a heterocyclic group, a halogen, anitrogen-substituted group, and a nitrogen-substituted ring compound.Additionally, A is a substituted divalent aromatic radical that includessubstituents selected from the group consisting essentially of hydrogenand the stable organic radical. The present invention further includes aphotochromic article comprising a host material and a photochromicamount of a naphthopyran compound and a method of making a naphthopyran.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Novel compounds have been discovered which enable high wavelengthactivation and deep coloring; which have acceptable fade rates and whichproduce colors on activation that are capable of being blended withblue-producing photochromic compounds to produce remarkably pleasinggray colors when the blends are activated by ultraviolet radiation. Thenovel naphthopyran compounds of the present invention may be generallyrepresented by graphic formula III as follows: ##STR5## For purposes ofthe present application, including the description and the claims, it isto be understood that graphical formula III includes all structuralisomers of the compounds represented by graphical formula III.

A variety of substituents may be placed on the pyran and the naphthoportion of the spiro naphthopyrans of the present invention. Forexample, the positions represented in graphic formula III by R₁, R₂, R₅,R₆, R₇, R₈, R₉, and R₁₀, respectively, may be filled with hydrogen; astable organic radical, such as alkyl, alkoxy, phenyl, naphthyl,cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, aroyloxy; a heterocyclicgroup; a halogen; a nitrogen-substituted group, such as amino or nitro;or a nitrogen-substituted ring compound, such as morpholino, piperidino,or piperazino.

Also in graphic formula III, the position represented by A is filled bya substituted divalent aromatic radical. The substituents of thedivalent aromatic radical may be hydrogen or a stable organic radicalsuch as alkyl, alkoxy, phenyl, naphthyl, cycloalkyl, furyl, alkoyl,alkoyloxy, aroyl, or aroyloxy. Additionally, the substituents of thesubstituted divalent may also be substituted with alkyl, alkoxy, phenyl,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, or aroyloxy.

The compounds represented by graphic formula III are derivatives of arylchromenes known as spironaphthopyrans. These inventive spironaphthopyrancompounds exhibit a surprising and highly desirable bathychromic shiftof the maximum activated wavelength. The bathychromic shift exhibited bythe inventive spironaphthopyran compounds provides photochromic specieswhich turn orange, reddish-orange, or red when activated by anultraviolet radiation source.

It has been found desirable to produce photochromic compounds withmaximum activated wavelengths approaching and even exceeding 500nanometers. Photochromic compounds with maximum activated wavelengthsnear or above 500 nanometers change from original states of color todeep shades of orange, reddish-orange, or red when activated byultraviolet light. The colored forms of the activated photochromiccompounds fade to the original, unactivated color states at ambienttemperatures when isolated from the ultraviolet light. As used in thisdisclosure, "intense photochromes" refers to photochromic compounds thatturn deep shades of orange, reddish orange, or red when activated.

The inventive naphthopyrans represented by graphic formula III,especially the intense photochromes, exhibit a deeper color and a largerbathychromic shift in the visible spectrum of the activated state ascompared to existing naphthopyrans. Indeed, the inventive naphthopyransrepresented by graphic formula III, especially the intense photochromes,approach a maximum activated wavelength of 500 nanometers; exhibit deepShades of orange, reddish-orange, or red; and include an acceptable fadecharacteristic. Surprisingly, one preferred naphthopyran of the presentinvention actually exceeds the 500 nanometer maximum activatedwavelength level.

Acceptable spironaphthopyran compounds of the present invention have amaximum activated wavelength when dissolved in either cyclohexane orchloroform of at least about 438 nanometers. More preferably, theinventive spironaphthopyrans have a maximum activated wavelength whendissolved in cyclohexane or chloroform of at least about 465 nanometers.Still more preferably, the spironaphthopyrans of the present inventionhave maximum activated wavelengths when dissolved in cyclohexane orchloroform of at least about 490 nanometers.

The intense spironapthopyrans of the present invention may be blendedwith one or more other photochromic compounds having maximum activationwavelengths different from that of the inventive intense photochromes tomake photochromic mixtures. Preferably, the other photochromic compoundsturn colors other than orange, reddish orange and red when activatedwith ultraviolet light. In one embodiment, one or more of the inventiveintense photochromes is preferably blended with another photochromiccompound, which has a different maximum activation wavelength and whichturns blue when activated with ultraviolet light, to make thephotochromic mixture. It has been discovered that photochromic mixturesthat include blends of the inventive intense photochromes andblue-turning photochromic compounds change to pleasing, desirable,intense shades of gray when activated by ultraviolet light, such as thatpresent in sunlight. The inventive spironaphthopyrans, alone, or thephotochromic mixtures may be desirably applied as coatings to, orincorporated within, articles, such as conventional synthetic plasticmaterials often used for optical elements.

Compounds of graphic formula III above may be prepared by reacting asuitable ketone precursor with a metal salt of an alkyne to make anintermediate. The intermediate is then reacted with either anunsubstituted naphthol or a substituted naphthol in the presence of acatalyst. The resultant material is then purified by recrystallization,column chromatography, or a combination of recrystallization and columnchromatography.

Suitable ketone precursors may be represented by graphic formula IV:##STR6## where the position represented by A is filled by thesubstituted divalent aromatic radical described with reference tographic formula III. As already indicated, the substituents of thesubstituted divalent aromatic radical, may be hydrogen, or a stableorganic radical such as alkyl, alkoxy, phenyl, naphthyl, cycloalkyl,furyl, alkoyl, alkoyloxy, aroyl, or aroyloxy. Some examples of suitableketone precursors consistent with graphical formula IV are shown below:##STR7##

The metal salt of the alkyne is preferably lithium acetylide and theorganic solvent is preferably tetrahydrofuran. The naphthol ispreferably either an unsubstituted 2-naphthol or a substituted2-naphthol. The catalyst is preferably a catalytic amount ofp-toluenesulfonic acid.

One particularly effective naphthopyran compound, consistent withgraphic formula III, is 8-methoxyspiro(3H-naphtho2,1b!pyran-2,9'-fluorene), which is represented by graphic formula V:##STR8## This compound has an activated maximum wavelength ofabsorption, when dissolved in chloroform, of about 492 nanometers whenirradiated with ultraviolet light. Additionally, when activated byultraviolet light, the 8-methoxyspiro(3H-naphtho2,1-b!pyran-2,9'-fluorene) turns a deep shade of orange. Furthermore,the 8-methhoxyspiro(3H-naphtho 2,1-b!pyran-2,9'-fluorene) blends withblue-turning photochromic compounds, such as substituted spiroindolinonaphthoxazine, to advantageously make one of the photochromic compoundblends that changes to a desirable, intense shade of gray when activatedby ultraviolet radiation.

Compounds represented by graphic formula III may be used in manyapplications of plastic substrates. For example, compounds representedby graphic formula III may be incorporated into a host material that isapplied to an article. Also, compounds represented by graphic formulaIII may be combined with the host material to make the article.Additionally, compositions that contain one or more of the photochromiccompounds represented by graphic formula III, such as the previouslymentioned photochromic mixtures, may be incorporated into the hostmaterial. The combination of the composition and host material, asalready noted, may be applied to or used to make the article. Also,compounds represented by graphic formula III and compositions containingone or more compounds represented by graphic formula III may beincorporated into a coating material that may be applied to the hostmaterial.

In another example, the article may be formulated for use as a coatingfor a suitable substrate. Polymerized organic materials, such assynthetic polymerized plastic often used to make optical elements, areexamples of the host material. Examples of the article include opticalelements, such as plano and ophthalmic lenses.

Non-exhaustive illustrations of suitable synthetic polymerized plasticsinclude polyacrylate, polycarbonate, polyvinyl alcohol, polyvinylacetate, polyvinyl chloride, polyurethane, cellulose ester andbis-polyol (allyl carbonate) monomer-based polymer. As used in thisdisclosure, the term bis-polyol (allyl carbonate) monomer and similarphrases are intended to mean and include the named monomer or prepolymerand any related monomer series contained therein. Some non-limitingexamples of bis-polyol (allyl carbonate) monomers include ethyleneglycol bis(allyl carbonate), diethylene glycol bis(2-methylallylcarbonate), diethylene glycol bis(allyl carbonate), propylene glycolbis(2-ethylallyl carbonate), 1-3-propanediol bis(allyl carbonate),1,3-butanediol bis(allyl carbonate), 1,4-butanediol bis(2,bromoallylcarbonate), dipropylene glycol bis(allyl carbonate), trimethylene glycolbis(2-ethylallyl carbonate), pentamethylene glycol bis(allyl carbonate),and isopropylidene bisphenol bis(allyl carbonate).

The amount of a particular one of the compounds represented by graphicformula III, or a particular composition containing one of the compoundsrepresented by graphic formula III, that is incorporated into the hostmaterial or the coating material is defined, for purposes of thisdisclosure, as the photochromic amount. The photochromic amount is notcritical, provided that a sufficient amount to produce a photochromiceffect perceptible to the human eye is used. The photochromic amountoften depends on the desired intensity of the color on activation of theparticular inventive naphthopyran and on the method of incorporation orapplication of the particular inventive naphthopyran. Typically, thephotochromic amount incorporated into or applied to the host material orincorporated into the coating material ranges from about 0.01 to about20 percent by weight, based on the weight of the host material or theweight of the coating material, as applicable.

The present invention is more particularly described in the followingexamples which are intended as illustrations only since numerousmodifications and variations within the scope of the general formulationwill be apparent to those skilled in the art.

EXAMPLE 1 Step 1

5.4 grams of 9-fluorenone were placed together with 5 grams of lithiumacetylide in 250 milliliters of tetrahydrofuran and stirred for 72hours. The 9-fluorenone served as the ketone precursor, which issubsequently referred to as compound K. The 9-fluorenone/lithiumacetylide/tetrahydrofuran mixture was poured over ice and diluted withwater to form an organic layer and an aqueous layer. The organic layerwas separated from the aqueous layer and dried with anhydrous sodiumsulfate. The dried organic layer was evaporated to obtain a solidmaterial. The solid material was then triturated with acetone. Thetriturated material was dissolved in a solvent and the solvent solutionwas cooled to yield a recrystallized compound. Nuclear magneticresonance (NMR) spectroscopy showed the recrystallized compound to be,9,9 fluorenediyl propargyl alcohol, a relatively pure substitutedpropargyl alcohol.

Step 2

1.24 grams of 9,9 fluorenediyl propargyl alcohol, the substitutedpropargyl alcohol from Step 1, were mixed with 1.05 grams of6-methoxy-2-naphthol in 200 milliliters of benzene. Twenty milligrams ofp-toluenesulfonic acid were then added and the mixture was stirred underreflux for 8 hours. The resultant mixture was cooled and washed with 10%aqueous sodium hydroxide. The organic solvent (benzene) was removedusing a rotary evaporator. The resulting material was dissolved in asolvent and the solvent solution was cooled to yield a recrystallizedproduct. The recrystallized product was shown to be the followingsubstituted 3H-naphtho 2, 1-b!pyran, 8-methoxyspiro(3H-naphtho2,1-b!pyran-3,9'-fluorene): ##STR9## by nuclear magnetic resonance (NMR)spectroscopy. The substituted 3H-naphtho 2,1-b!pyran product, insubsequent examples, is referred to as compound P.

EXAMPLE 2

The procedure of Example 1 was repeated in Example 2 except that thecompound K used in Example 2 was 1-tetralone; the substituted propargylalcohol produced in Step 1 was other than 9,9 fluorenediyl propargylalcohol; the mount of substituted propargyl alcohol from Step 1 that wasused in Step 2 was 1.03 grams; and the product compound P was8-methoxyspiro(3H-naphtho 2,1-b!pyran-3,1'-tetralone), the structure ofwhich is as follows: ##STR10##

EXAMPLE 3

The procedure of Example 1 was repeated in Example 3 except that thecompound K used in Example 3 was 6,7-dimethoxy-1-tetralone; thesubstituted propargyl alcohol produced in Step 1 was other than 9,9fluorenediyl propargyl alcohol; the amount of substituted propargylalcohol from Step 1 that was used in Step 2 was 1.39 grams; and theproduct compound P was 6',7'-dimethoxy-8-methoxyspiro(3H-naphtho2,1-b!pyran-3,1'-tetralone), the structure of which is as follows:##STR11##

EXAMPLE 4

The procedure of Example 1 was repeated in Example 4 except that thecompound K used in Example 4 was 7-methoxy-1-tetralone; the substitutedpropargyl alcohol produced in Step 1 was other than 9,9 fluorenediylpropargyl alcohol; the amount of substituted propargyl alcohol from Step1 that was used in Step 2 was 1.21 grams; and the product compound P was7'-methoxy-8-methoxyspiro(3H-naphtho 2,1-b!pyran-3,1'-tetralone), thestructure of which is as follows: ##STR12##

EXAMPLE 5

The procedure of Example 1 was repeated in Example 5 except that thecompound K used in Example 5 was 2,3-diphenyl-1-tetralone; thesubstituted propargyl alcohol produced in Step 1 was other than 9,9fluorenediyl propargyl alcohol; the amount of substituted propargylalcohol from Step 1 that was used in Step 2 was 1.95 grams; and theproduct compound P was 2',3'-diphenyl-8-methoxyspiro(3H-naphtho2,1-b!pyran-3,1'-tetralone), the structure of which is as follows:##STR13##

EXAMPLE 6

The procedure of Example 1 was repeated in Example 6 except that thecompound K used in Example 6 was 2-methyl-1-tetralone; the substitutedpropargyl alcohol produced in Step 1 was other than 9,9 fluorenediylpropargyl alcohol; the amount of substituted propargyl alcohol from Step1 that was used in Step 2 was 1.18 grams; and the product compound P was2'-methyl-8-methoxyspiro(3H-naphtho 2,1-b!pyran-3,1'-tetralone), thestructure of which is as follows: ##STR14##

EXAMPLE 7

The procedure of Example 1 was repeated in Example 7 except that thecompound K used in Example 7 was 2-methyl-1-indanone; the substitutedpropargyl alcohol produced in Step 1 was other than 9,9 fluorenediylpropargyl alcohol; the amount of substituted propargyl alcohol from Step1 that was used in Step 2 was 1.03 grams, and the product compound P was2'-methyl-8-methoxyspiro(3H-naphtho 2,1-b!pyran-3,1'-indan), thestructure of which is as follows: ##STR15##

EXAMPLE 8

The procedure of Example 1 was repeated in Example 8 except that thecompound K used in Example 8 was 2,3-diphenyl-1-indenone; thesubstituted propargyl alcohol produced in Step 1 was other than 9,9fluorenediyl propargyl alcohol; the amount of substituted propargylalcohol from Step 1 that was used in Step 2 was 1.85 grams, and theproduct compound P was 2',3'-diphenyl-8-methoxyspiro(3H-naphtho2,1-b!pyran-3,1'-indene), the structure of which is as follows:##STR16##

EXAMPLE 9 Step 1

5.4 grams of 9-fluorenone were placed together with 5 grams of lithiumacetylide in 250 milliliters of tetrahydrofuran and stirred for 72hours. The 9-fluorenone served as compound K, the ketone precursor. The9-fluorenone/lithium acetylide/tetrahydrofuran mixture was poured overice and diluted with water to form an organic layer and an aqueouslayer. The organic layer was separated from the aqueous layer and driedwith anhydrous sodium sulfate. The dried organic layer was evaporated toobtain a solid material. The solid material was then triturated withacetone. The triturated material, was dissolved in a solvent and thesolvent solution was cooled to yield a recrystallized compound. Nuclearmagnetic resonance (NMR) spectroscopy showed the recrystallized compoundto be, 9,9 fluorenediyl propargyl alcohol, a relatively pure substitutedpropargyl alcohol.

Step 2

1.24 grams of 9,9 fluorenediyl propargyl alcohol, the substitutedpropargyl alcohol, were mixed with 0.87 grams of 2-naphthol in 200milliliters of benzene. Twenty milligrams of p-toluenesulfonic acid werethen added and the mixture was stirred under reflux for 8 hours. Theresultant mixture was cooled and washed with 10% aqueous sodiumhydroxide. The organic solvent (benzene) was removed using a rotaryevaporator. The resulting material was dissolved in a solvent and thesolvent solution was cooled to yield a recrystallized product. Therecrystallized product compound P was shown to be the followingsubstituted 3H-naphtho 2,1-b!pyran, spiro(3H-naphtho2,1-b!pyran-3,9'-fluorene): ##STR17## by nuclear magnetic resonance(NMR) spectroscopy.

EXAMPLE 10

The procedure of Example 9 was repeated in Example 10 except that thecompound K used in Example 10 was 2,3-diphenyl-1-tetralone; thesubstituted propargyl alcohol produced in Step 1 was other than 9,9fluorenediyl propargyl alcohol; the amount of substituted propargylalcohol from Step 1 that was used in Step 2 was 1.95 grams; and theproduct compound P was 2',3'-diphenylspiro(3H-naphtho2,1-b!pyran-3,1'-tetralone), the structure of which is as follows:##STR18##

EXAMPLE 11

The procedure of Example 9 was repeated in Example 11 except that thecompound K used in Example 11 was 2-methyl-1-tetralone; the substitutedpropargyl alcohol produced in Step 1 was other than 9,9 fluorenediylpropargyl alcohol; the amount of substituted propargyl alcohol from Step1 that was used in Step 2 was 1.18 grams; and the product compound P was2'-methylspiro(3H-naphtho 2,1-b!pyran-3,1'-tetralone), the structure ofwhich is as follows: ##STR19##

EXAMPLE 12

The procedure of Example 9 was repeated in Example 12 except that thecompound K used in Example 12 was 2-methyl-1-indanone; the substitutedpropargyl alcohol produced in Step 1 was other than 9,9 fluorenediylpropargyl alcohol; the amount of substituted propargyl alcohol from Step1 that was used in Step 2 was 1.03 grams; and the product compound P was2'-methylspiro(3H-naphtho 2,1-b!pyran-3,1'-indan), the structure ofwhich is as follows: ##STR20##

EXAMPLE 13

The procedure of Example 9 was repeated in Example 13 except that thecompound K used in Example 13 was 2,3-diphenyl-1-indenone; thesubstituted propargyl alcohol produced in Step 1 was other than 9,9fluorenediyl propargyl alcohol; the amount of substituted propargylalcohol from Step 1 that was used in Step 2 was 1.85 grams, and theproduct compound P was 2',3'-diphenylspiro(3H-naphtho2,1-b!pyran-3,1'-indene, the structure of which is as follows: ##STR21##

Comparative Example 1 Step 1

Five grams of benzophenone were placed together with 5 grams of lithiumacetylide in 250 milliliters of tetrahydrofuran and stirred for 72hours. The benzophenone served as the ketone precursor. Thebenzophenone/lithium acetylide/tetrahydrofuran mixture was poured overice and diluted with water to form an organic layer and an aqueouslayer. The organic layer was separated from the aqueous layer and driedwith anhydrous sodium sulfate. The dried organic layer was evaporated toobtain a solid material. The solid material was then triturated withacetone. The triturated material was dissolved in a solvent and thesolvent solution was cooled to yield a recrystallized compound. Nuclearmagnetic resonance (NMR) spectroscopy showed the resultant material tobe a relatively pure substituted propargyl alcohol, diphenyl propargylalcohol.

Step 2

1.25 grams of the substituted propargyl alcohol, diphenyl propargylalcohol, were mixed with a stoichiometric amount, 0.87 grams, of6-methoxy-2-naphthol in 200 milliliters of benzene. Twenty milligrams ofp-toluenesulfonic acid were then added and the mixture was stirred underreflux for 8 hours. The resultant mixture was cooled and washed with 10%aqueous sodium hydroxide. The organic solvent (benzene) was removedusing a rotary evaporator. The resulting material was dissolved in asolvent and the solvent solution was cooled to yield a recrystallizedproduct. The recrystallized product was shown to be a substituted3H-naphtho 2,1-b!pyran, specifically, 3,3-diphenyl-8-methoxy-3H-naphtho2,1-b!pyran, by nuclear magnetic resonance (NMR) spectroscopy.

DETERMINATION OF MAXIMUM ABSORPTION WAVELENGTH AND FADE TIME

Each of the photochromic compounds (compound P) formed in step 2 ofExamples 1-13 and Comparative Example 1 were independently dissolved inseparate containers of chloroform. Additionally, a purchased sample of3,3-diphenyl-naphtho-3H 2,1-b!pyran, identified as Comparative Example2, was dissolved in a separate container of chloroform.

Each of the chloroform-dissolved photochromic compounds of Examples 1-13and Comparative Examples 1-2 were then irradiated with ultraviolet lightwith a maximum wavelength of 350 nanometers and were measured formaximum absorption wavelength) λ_(max). The fade time, T_(1/2) was thendetermined for each of the irradiated compounds. The fade time for aparticular chloroform dissolved photochromic compound is defined as thetime interval, at room temperature (72° F.), for the absorbance of theactivated form of the chloroform-dissolved photochromic compound todecrease to 1/2 of the maximum absorbance, after the photochromiccompound is isolated from the activating source of ultraviolet light.The maximum absorption wavelength and fade time determined for each ofthe irradiated photochromic compounds of Examples 1-13 and ComparativeExamples 1-2 are presented in Table 1:

                  TABLE 1                                                         ______________________________________                                                  λ.sub.max                                                                             T.sub.1/2                                                      (Nanometers)   (Seconds)                                                      Cyclohexane                                                                            Chloroform                                                                              Chloroform                                       ______________________________________                                        COMPOUND                                                                      EXAMPLE                                                                        1          478        492       20                                            2          465        474       15                                            3          *          445       *                                             4          **         **        **                                            5          **         476       13                                            6          **         468       1.2                                           7          **         478       396                                           8          **         512       64                                            9          438        445       10                                           10          **         **        **                                           11          **         444       *                                            12          **         **        **                                           13          **         454       35                                           COMPARATIVE                                                                   EXAMPLE                                                                        1          451        472       10                                            2          415        435       13                                           ______________________________________                                         Comparative Example 2: Purchased 3,3diphenyl-naphtho-3H 2,1b!pyran            *Fades too fast to obtain readings                                            **Not Determined                                                         

The values presented in Table 1 illustrate that the photochromiccompound of Example 1, 8-methoxyspiro(3H-naphtho2,1-b!pyran-3,9'-fluorene), has a longer maximum wavelength ofactivation than does the photochromic compound of Comparative Example 1,3,3-diphenyl-8-methoxy-3H-naphtho 2,1-b!pyran. The Table 1 values alsoillustrate that the photochromic compound of Example 9, spiro(3H-naphtho2,1-b!pyran-3,9'-fluorene), exhibits longer maximum wavelengths ofactivation than does the photochromic compound of Comparative Example 2,3,3-diphenyl-naphtho-3H 2,1-b!pyran. The longer maximum wavelengths ofactivation exhibited by the inventive photochromic compounds of Examples1-13 are desirable characteristics for substituted naphthopyranphotochromic compounds.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. A photochromic article comprising a host materialand a photochromic amount of a naphthopyran compound, the naphthopyrancompound represented by the formula: ##STR22## wherein, R₁, R₂, R₅, R₆,R₇, R₈, R₉, and R₁₀ are each selected from the group consisting ofhydrogen, alkyl, alkoxy, phenyl, naphthyl, cycloalkyl, furyl, alkoyl,alkoyloxy, aroyl, aroyloxy, a heterocyclic group, a halogen, amino,nitro, morpholino, piperidino, and piperazino; andA is a substituteddivalent aromatic radical, the substituents of the divalent aromaticradical selected from the group consisting of hydrogen, alkyl, alkoxy,phenyl, naphthyl, furyl, alkoyl, alkoyloxy, aroyl, aroyloxy, andcycloalkyl with the proviso that cyclopentyl and cyclohexyl areexcluded.
 2. The photochromic article of claim 1 wherein R₁, R₂, R₅, R₆,R₇, R₈, R₉, and R₁₀ are each selected from the group consisting ofhydrogen, C1-C2 alkyl, methoxy and ethoxy.
 3. The photochromic articleof claim 2 wherein the substituents of the divalent aromatic radical areselected from the group consisting of hydrogen, phenyl, naphthyl, alkyl,alkoxy, and cycloalkyl.
 4. The photochromic article of claim 1 whereinthe host material is made of a polymerized organic compound.
 5. Thephotochromic article of claim 4 wherein the polymerized organic compoundis selected from the group consisting of polyacrylate, polycarbonate,polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, polyurethane,cellulose ester, and a polymer of bis-polyol(allyl carbonate) monomer.6. The photochromic article of claim 1 wherein the naphthopyran compoundis present in an amount of from about 0.01 to about 20 percent byweight, based on the weight of the host material.
 7. The photochromicarticle of claim 1 wherein the article is an optical element.
 8. Thephotochromic article of claim 1 wherein the optical element is a lens.9. The photochromic article of claim 1 wherein the article is a coatingfor a substrate.
 10. The photochromic article of claim 1, the articlefurther comprising one or more additional photochromic compounds, thenaphthopyran compound and the additional photochromic compounds havingdifferent maximum wavelengths of activation.
 11. The photochromicarticle of claim 1 wherein the naphthopyran compound is selected fromthe group consisting of: ##STR23##
 12. The photochromic article of claim1 wherein the substituted divalent aromatic radical is selected from thegroup consisting of: ##STR24##
 13. The photochromic article of claim 1wherein the substituted divalent aromatic radical is represented by theformula: ##STR25## wherein R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ areselected from the group consisting of hydrogen, alkyl, alkoxy, phenyl,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy. 14.The photochromic article of claim 1 wherein R₁, R₂, R₅, R₆, R₇, R₈, R₉,and R₁₀ are each selected from the group consisting of furyl, alkoyl,aroyl, aroyloxy, and the heterocyclic group.
 15. The photochromicarticle of claim 1 wherein eitherthe substituents of the divalentaromatic radical are selected from the group consisting of hydrogen,alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, provided that the divalent aromatic radical is substitutedwith at least one substituent selected from the group consisting ofalkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, and provided that at least one of the substituents of thedivalent aromatic radical is substituted with a radical selected fromthe group consisting of alkyl, alkoxy, phenyl, naphthyl, cycloalkyl,furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy; or the substituents ofthe divalent aromatic radical are selected from the group consisting ofhydrogen, alkyl, phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl,alkoyloxy, aroyl, and aroyloxy, provided that at least one of thesubstituents of the divalent aromatic radical is substituted with aradical selected from the group consisting of phenyl, naphthyl,cycloalkyl, furyl, alkoyl, aroyl, and aroyloxy.
 16. The photochromicarticle of claim 1 wherein the divalent aromatic radical includes afive-membered ring radical that is attached to the pyran ring of thenaphthopyran compound, the substituents of the divalent aromatic radicalselected from the group consisting of hydrogen, alkyl, phenyl, alkoxy,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy,provided that at least one of the substituents of the divalent aromaticradical is selected from the group consisting of cycloalkyl, furyl,alkoyl, aroyl, and aroyloxy.
 17. The photochromic article of claim 16wherein the five-membered ring radical that is attached to the pyranring is represented by the formula: ##STR26## wherein: R₁₁ and R₁₂ areeither selected from the group consisting of hydrogen, alkyl, phenyl,alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, or jointly represent a first aromatic ring radical;R₁₃ and R₁₄are either selected from the group consisting of hydrogen, alkyl,phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl,and aroyloxy, or jointly represent a second aromatic ring radical; andfirst aromatic ring radical and the second aromatic ring radical havingsubstituents selected from the group consisting of hydrogen, alkyl,phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl,and aroyloxy.
 18. The photochromic article of claim 19 wherein the firstaromatic ring radical and the second aromatic ring radical are selectedfrom the group consisting of phenyl and naphthyl.
 19. The photochromicarticle of claim 1 wherein the divalent aromatic radical includes asix-membered ring radical that is attached to the pyran ring of thenaphthopyran compound, the substituents of the divalent aromatic radicalselected from the group consisting of hydrogen, alkyl, phenyl, alkoxy,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy,provided that at least one of the substituents of the divalent aromaticradical is selected from the group consisting of phenyl, naphthyl,cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy.
 20. Thephotochromic article of claim 19 wherein the six-membered ring radicalthat is attached to the pyran ring is represented by the formula:##STR27## wherein R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are selected from thegroup consisting of hydrogen, alkyl, phenyl, alkoxy, naphthyl,cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy, provided thatany adjacent two of R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ may jointly represent anaromatic ring radical having substituents selected from the groupconsisting of hydrogen, alkyl, phenyl, alkoxy, naphthyl, cycloalkyl,furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy.
 21. The photochromicarticle of claim 20 wherein the substituted aromatic ring radical isselected from the group consisting of phenyl and naphthyl.
 22. Anaphthopyran compound, the naphthopyran compound represented by theformula: ##STR28## wherein, R₁, R₂, R₅, R₆, R₇, R₈, R₉, and R₁₀ are eachselected from the group consisting of hydrogen, a heterocyclic group,halogen, alkyl, alkoxy, phenyl, naphthyl, cycloalkyl, furyl, alkoyl,alkoyloxy, aroyl, aroyloxy, amino, nitro, morpholino, piperidino, andpiperazino; andA is a substituted divalent aromatic radical, thesubstituents of the divalent aromatic radical selected from the groupconsisting of hydrogen, alkyl, alkoxy, phenyl, naphthyl, furyl, alkoyl,alkoyloxy, aroyl, aroyloxy, and cycloalkyl with the proviso thatcyclopentyl and cyclohexyl are exluded.
 23. The naphthopyran compound ofclaim 22 wherein the naphthopyran compound is selected from the groupconsisting of: ##STR29##
 24. The naphthopyran compound of claim 22wherein the substituted divalent aromatic radical is selected from thegroup consisting of: ##STR30##
 25. The naphthopyran compound of claim 22wherein the substituted divalent aromatic radical is represented by theformula: ##STR31## wherein R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ areselected from the group consisting of hydrogen, alkyl, alkoxy, phenyl,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy. 26.The naphthopyran compound of claim 22 wherein R₁, R₂, R₅, R₆, R₇, R₈,R₉, and R₁₀ are each selected from the group consisting of furyl,alkoyl, aroyl, aroyloxy, and the heterocyclic group.
 27. Thenaphthopyran compound of claim 22 wherein eitherthe substituents of thedivalent aromatic radical are selected from the group consisting ofhydrogen, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl,and aroyloxy, provided that the divalent aromatic radical is substitutedwith at least one substituent selected from the group consisting ofalkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, and provided that at least one of the substituents of thedivalent aromatic radical is substituted with a radical selected fromthe group consisting of alkyl, alkoxy, phenyl, naphthyl, cycloalkyl,furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy; or the substituents ofthe divalent aromatic radical are selected from the group consisting ofhydrogen, alkyl, phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl,alkoyloxy, aroyl, and aroyloxy, provided that at least one of thesubstituents of the divalent aromatic radical is substituted with aradical selected from the group consisting of phenyl, naphthyl,cycloalkyl, furyl, alkoyl, aroyl, and aroyloxy.
 28. The naphthopyrancompound of claim 22 wherein the divalent aromatic radical includes afive-membered ring radical that is attached to the pyran ring of thenaphthopyran compound, the substituents of the divalent aromatic radicalselected from the group consisting of hydrogen, alkyl, phenyl, alkoxy,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy,provided that at least one of the substituents of the divalent aromaticradical is selected from the group consisting of cycloalkyl, furyl,alkoyl, aroyl, and aroyloxy.
 29. The naphthopyran compound of claim 28wherein the five-membered ring radical that is attached to the pyranring is represented by the formula: ##STR32## wherein: R₁₁ and R₁₂ areeither selected from the group consisting of hydrogen, alkyl, phenyl,alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, or jointly represent a first aromatic ring radical;R₁₃ and R₁₄are either selected from the group consisting of hydrogen, alkyl,phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl,and aroyloxy, or jointly represent a second aromatic ring radical; andfirst aromatic ring radical and the second aromatic ring radical havingsubstituents selected from the group consisting of hydrogen, alkyl,phenyl, alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl,and aroyloxy.
 30. The naphthopyran compound of claim 29 wherein thefirst aromatic ring radical and the second aromatic ring radical areselected from the group consisting of phenyl and naphthyl.
 31. Thenaphthopyran compound of claim 22 wherein the divalent aromatic radicalincludes a six-membered ring radical that is attached to the pyran ringof the naphthopyran compound, the substituents of the divalent aromaticradical selected from the group consisting of hydrogen, alkyl, phenyl,alkoxy, naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, andaroyloxy, provided that at least one of the substituents of the divalentaromatic radical is selected from the group consisting of phenyl,naphthyl, cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy. 32.The naphthopyran compound of claim 31 wherein the six-membered ringradical that is attached to the pyran ring is represented by theformula: ##STR33## wherein R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ are selected fromthe group consisting of hydrogen, alkyl, phenyl, alkoxy, naphthyl,cycloalkyl, furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy, provided thatany adjacent two of R₁₁, R₁₂, R₁₃, R₁₄, and R₁₅ may jointly represent anaromatic ring radical having substituents selected from the groupconsisting of hydrogen, alkyl, phenyl, alkoxy, naphthyl, cycloalkyl,furyl, alkoyl, alkoyloxy, aroyl, and aroyloxy.
 33. The naphthopyrancompound of claim 31 wherein the aromatic ring radical is selected fromthe group consisting of phenyl and naphthyl.